why?????

#include<bits/stdc++.h>
using namespace std;
int main()
{
	int a;
	cin>>a;
	if(a==1)
		cout<<1;
	if(a==2)
		cout<<2;
	if(a==3)
		cout<<3;
	if(a==4)
		cout<<4;
	if(a==5)
		cout<<5;
	if(a==6)
		cout<<6;
	if(a==7)
		cout<<7;
	if(a==8)
		cout<<8;
	if(a==9)
		cout<<9;
	if(a==10)
		cout<<10;
	if(a>=11 && a<=21)
		cout<<11;
	if(a>=22 && a<=32)
		cout<<12;
	if(a>=33 && a<=43)
		cout<<13;
	if(a>=44 && a<=54)
		cout<<14;
	if(a>=55 && a<=65)
		cout<<15;
	if(a>=66 && a<=76)
		cout<<16;
	if(a>=77 && a<=87)
		cout<<17;
	if(a>=88 && a<=98)
		cout<<18;
	if(a>=99 && a<=110)
		cout<<19;
	if(a>=111 && a<=221)
		cout<<20;
	if(a>=222 && a<=332)
		cout<<21;
	if(a>=333 && a<=443)
		cout<<22;
	if(a>=444 && a<=554)
		cout<<23;
	if(a>=555 && a<=665)
		cout<<24;
	if(a>=666 && a<=776)
		cout<<25;
	if(a>=777 && a<=887)
		cout<<26;
	if(a>=888 && a<=998)
		cout<<27;
	if(a>=999 && a<=1110)
		cout<<28;
	if(a>=1111 && a<=2025)
		cout<<29;
	return 0;
 }